Low Thermal Resistance of Diamond-AlGaN Interfaces Achieved Using Carbide Interlayers

2024/08/15 by Henry T. Aller, Aller, Henry T., Thomas W. Pfeifer +27
Engineering · Materials Science · Physics and Astronomy · #Advanced ceramic materials synthesis #Atomic Physics (physics.atom-ph) #FOS: Physical sciences #GaN-based semiconductor devices and materials #Materials Science (cond-mat.mtrl-sci) #Metal and Thin Film Mechanics

paper · pdf · doi:10.48550/arxiv.2408.08076

openalex publication_date 2024/08/15 · openalex created_date 2025/01/03 · openalex updated_date 2026/07/28

Abstract

This study investigates thermal transport across nanocrystalline diamond/AlGaN interfaces, crucial for enhancing thermal management in AlGaN/AlGaN-based devices. Chemical vapor deposition growth of diamond directly on AlGaN resulted in a disordered interface with a high thermal boundary resistance (TBR) of 20.6 m²-K/GW. We employed sputtered carbide interlayers (e.g., B₄C, SiC, B₄C/SiC) to reduce thermal boundary resistance in diamond/AlGaN interfaces. The carbide interlayers resulted in record-low thermal boundary resistance values of 3.4 and 3.7 m²-K/GW for Al_0.65Ga_0.35N samples with B₄C and SiC interlayers, respectively. STEM imaging of the interface reveals interlayer thicknesses between 1.7-2.5 nm, with an amorphous structure. Additionally, Fast-Fourier Transform (FFT) characterization of sections of the STEM images displayed sharp crystalline fringes in the AlGaN layer, confirming it was properly protected from damage from hydrogen plasma during the diamond growth. In order to accurately measure the thermal boundary resistance we develop a hybrid technique, combining time-domain thermoreflectance and steady-state thermoreflectance fitting, offering superior sensitivity to buried thermal resistances. Our findings underscore the efficacy of interlayer engineering in enhancing thermal transport and demonstrate the importance of innovative measurement techniques in accurately characterizing complex thermal interfaces. This study provides a foundation for future research in improving thermal properties of semiconductor devices through interface engineering and advanced measurement methodologies.

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